Silicon oscillators have conventionally been used in which an oscillation element is formed of a silicon wafer by a semiconductor manufacturing technique. A silicon oscillator is lower in cost and easier to be downsized than a crystal oscillator, but has a problem of a large fluctuation of frequency due to the temperature.
Therefore, in a semiconductor integrated circuit that incorporates a silicon oscillator and a counter using the oscillating frequency of the silicon oscillator as a clock, an operation temperature of the semiconductor integrated circuit is estimated, and a count value of the counter is corrected in accordance with the estimated temperature.
In this process, the correction is required to be performed by considering a large characteristic fluctuation of the semiconductor element due to manufacturing variations.